TDOA/GPS hybrid wireless location system

Abstract

A method and system for enhancing the accuracy and robustness of locations determined for a mobile wireless transceiver in a cellular telephone communications system integrates location-related information both from an assisted GPS device embedded in the mobile unit and from infrastructure-based facilities that extract signal characteristic data at networked base stations. Available supporting collateral information may be additionally evaluated in the location determinations to provide location estimates of enhanced robustness and accuracy.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to wireless location systems, and more particularly to a wireless location system that employs both infrastructure-based and handset-based approaches for locating wireless devices. Some of the exemplary aspects of the present invention are particularly suited to a wireless location system and related methods and subsystems compatible with the Global System for Mobile Communication, or GSM. It should be noted, however, that although aspects of the systems and methods described herein relate specifically to a GSM system, the claims at the end of this specification are not to be construed as limited to a GSM system, except as they may be explicitly so limited. BACKGROUND OF THE INVENTION [0002] The present invention relates to the determination of the location of a mobile radio-frequency transceiver operating within the operational domain of a wireless communications network. In particular, the mobile units of primar...

AI Technical Summary

Benefits of technology

[0014] For example, in one presently preferred implementation of the invention, the location of a mobile station (MS) equipped with embedded GPS signal reception capability is determined using both GPS data and extracted location-related signal characteristics. The inventive method includes the steps of receiving GPS data at a land station, the GPS data being received from a MS to be located; at a land station equipped with location-measurement facilities, receiving from the MS to be located a communications-band signal, and using the location-measurement facilities to extract location-related characteristic data from the communications-band signal; and at a land station equipped for location-determination calculations, performing location-determination calculations using the GPS data and the extracted location-related characteristic data to derive an estimated location for the MS. In addition, the method may further include providing assistance data to the MS to be located. The assistance data enables the MS to receive GPS coarse / acquisition (C / A) signals and extract TOA or pseudorange measures, which can then be communicated to the land station equipped with location-measurement facilities. Further, where the GPS data and the extracted location-related characteristic data are provided at separate land stations, these may be communicated to the land station equipped for location-determination calculations, thereby enabling the location-determination function to be carried out. As explained below, the location-related characteristic data extracted from the communications-band signal may include time of arrival (TOA) data, time difference of arrival (TDOA) data, angle of arrival (AOA) data, signal strength or propagation loss (PL) data, and / or timing advance (TA) data. In addition, the inventive method may advantageously include the use of collateral information in performing the location-determination calculations. Finally, the method may advantageously be employed to achieve applicable Federal Communications Commission (FCC) accuracy requirements for E-911.

Problems solved by technology

To date, the system architectures implemented for the diverse localization approaches have not readily supported the information integration needs.

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